Introduction: Sporterize a Military Surplus Rifle
Over the past couple of years, I've developed a penchant for taking old military surplus rifles and turning them into some pretty respectable shooters - a process known as "sporterizing." In this Instructable, I walk through the basic steps taken to sporterize a couple of WWII rifles.
The term "sporterize" can mean different things to different people, but in general it's a term applied to military firearms that are modified and re-purposed to more "sporting" use such as target shooting or hunting. Military surplus rifles are attractive because of the low initial cost and the reasonable availability of inexpensive surplus ammunition. My goal was to convert these WWII "relics" into more modern rifles that are accurate and fun to shoot (most military firearms are fairly punishing to shoot in their original form) while trying to stay within a reasonable budget. Obviously, the more you can do yourself - i.e. without having to go to a gunsmith - the less expensive the project. Admittedly, it's likely that a person who just wanted a hunting rifle could probably buy a new basic-model rifle for less money than if they sporterized an old military surplus rifle - but - for me personally, I think I enjoy the process as much as the results. My Dad always said I never could leave well-enough alone. :)
This instructable is meant to be more of a general guide than a specific set of instructions. Why? Because there are simply too many variables to cover. There are ways to cut costs from what I've done, and ways to make things a lot more expensive, so I'll try to be good about explaining my decisions. I'm also combining two projects into one because the overall sporterizing process is fairly generic and the pictures from one project kind of fill in where the other is lacking. The rifles in this project are a late-1940's Yugoslavian 8mm Mauser 24/47 and a 1939 Russian Mosin Nagant 91/30. (Just for the record, neither of these were super-clean, numbers-matching guns - they were arsenal-refurb Frankenguns - so the "collectors" out there can breathe a sigh of relief).
What does it cost? Depending on how much of the work you can (or want) to do, parts and materials costs are in the neighborhood of $500-$700 including the rifle and optic if you're starting empty handed - less if you already have some of the components. The Mosin I bought cost $135, the Mauser, $265 (these costs are included in the $500-700 estimate).
A NOTE ON SAFETY: PLEASE do not attempt to take on a project like this if you are unfamiliar with the condition, mechanical operation, and critical dimensions of your firearm. If words like "headspacing" are unfamiliar to you, you will probably want to hand off any barrel or receiver modifications to someone more knowledgeable - like a gunsmith. I can't / won't be held responsible for you if you do something silly - so don't let your ego outrun your skillset. If at any time you're unsure about exactly what you're doing and the possible things that could go wrong (and what to watch for), you should defer to a professional - 'nuff said ;)
Step 1: Removing Iron Sights
The majority of the "work" in sporterizing centers around the barrel. Typically, the barrel of the rifle will be shortened and the iron sights removed in preparation for the installation of a scope rail / mount and optic. Sight removal, however, is not a requirement unless the sights will get in the way of other work such as re-contouring the barrel on a lathe. In some cases, leaving the sights in place can be a requirement of some aftermarket scope rails that use the bases of the existing sights to mount rails to - so - what you do will depend on how you want to mount your optics - there are a lot of options out there.
In the case of both the Mauser and the Mosin, I decided to shorten the barrels - which would remove the front sights - and thereby make the rear sight useless to me .... so I removed the rear sights as well. (Again, there are certain scope mounts that make use of the rear sight base, so, how you choose to mount your optics will drive what you do with the rear sight.) Each make and model of rifle has it's own way of attaching the sights. In the case of the Mauser, the sight bases were soldered on with low-temperature solder - and in the case of the Mosin, the sight bases were press-fit and pinned (sometimes they're soldered, too). A quick search for "Mauser / Mosin sight removal" turned up a number of sites that had great information on how to do it. Neither rifle required any exotic tools - just a punch, hammer, and a propane torch.
Step 2: Barrel Work
A NOTE ON BARREL LENGTH: Do NOT shorten your barrel to under 16" on a rifle! If you do, you would be building what is known as an SBR - or Short Barreled Rifle, and the ATF haaates that. SBR's require NFA paperwork, registration, fees, bureaucrats, etc, etc - so save yourself the hassle and keep your barrels comfortably over 16".
Barrel length can be kind of an arbitrary decision. I shortened the Mosin's barrel from 28" to 22" and the Mauser from 23" to 18" ... for no particular reason. Just be aware that if you do shorten the barrel, you might be hurting the accuracy of what that barrel is capable of with military surplus ammo. Most milsurp ammo was spec'd out with a specific barrel length in mind - so - if you intend on shortening your barrel AND you want it to shoot well with milsurp ammo, it would be worth doing some research and finding out if there is a barrel length that seems to work well for other people. If, however, you intend to handload your ammo (I do) barrel length is a bit less critical.
Shortening, re-crowning, and threading a barrel aren't horribly complex tasks and can successfully be accomplished with the barrel on the receiver. There are hand-tools available to cut, crown, and thread a barrel, but they are pretty expensive. Thankfully, these tools can be rented - do a search for "gunsmith tool rentals" - here is just one rental source: barrel tools for rent). The tools you will probably need to rent are: 1) a crown reamer of the appropriate caliber, and 2) a piloted barrel die or barrel threading die of the appropriate thread diameter and pitch (IF you intend to install a muzzle device). The barrel die will only work if your desired thread diameter is pretty close to the barrel diameter at the point of your cut. Any larger, and you'll have to have the barrel turned down - at which point you may as well have it threaded, too. (FYI, typical .30 caliber barrel threads are 5/8-24).
IMPORTANT NOTE: A piloted barrel die (for threading a barrel) will not provide the accuracy required for use with a suppressor. If you plan on using a suppressor, you will need to thread the barrel on a lathe making sure that the threads are concentric with the bore - and - make sure you have enough material for a decent shoulder to thread up against. If like me, however, you just plan on using a muzzle brake, the piloted barrel die will provide suitable accuracy.
If you are fortunate (as I am), and have access to a lathe and a barrel vice, it's probably just as easy to remove the barrel from the receiver and do all your crowning and threading work on the lathe.
The basic steps I went through were:
1. Measure and cut the barrel to length with a hacksaw.
2. Mount the barrel in the lathe and do any clean-up / reshaping
3. Re-position the barrel and re-crown.
4. Thread the barrel to specifications (in the case of both barrels, 5/8 - 24)
How to measure your barrel length ("official" length):
1. Close the bolt on your rifle
2. Slide a dowel rod (or straightened coathanger) gently(!) down the bore of the barrel until it stops on the face of the bolt.
3. Put a mark on the dowel flush with the front of the muzzle.
4. Remove the dowel and measure from the end that you put into the barrel to the mark - this is your official barrel length.
Shortening to length:
1) Subtract your desired length from the measured length of the barrel.
2) Take the result from step 1 and measure back from the muzzle this distance on the barrel - and mark it. You might want to mark it just a bit longer (i.e. cut less barrel off) initially so that you have room to clean up the cut. 1/16" to 1/8" should be plenty. (Remember: keep it longer than 16")
3) Clean up the end of the barrel with a file or sander. This will save you time and effort if you are going to be using a crown reamer to crown your barrel.
Step 3: Stock Work and Triggers
Replacing the Stock:
Chances are, you're going to replace the stock on the rifle. The good news is that there is a pretty broad range of stocks available for most popular military rifles from places like Boyd's Gunstocks, Richards Microfit, Amazon, and Brownells. I chose Boyd's Thumbhole stocks for both rifles as they are fairly inexpensive and very comfortable for me. Due to the fact that there are a lot of different variations of the Mauser barrel / receiver, it would be pretty difficult for a manufacturer to keep them all in stock - not to mention that there would be a lot of problems with people ordering the correct one - so - Boyd's carries "partially inlet," unfinished stocks for Mausers. These stocks require the owner to complete the inletting to best fit their rifle. The stock for the Mosin Nagant, however, came finished.
Completing the inletting is pretty straight-forward. Ideally, the receiver will eventually set in the stock with only the front lug area and rear tang area in contact. The barrel and receiver should be pretty much free-floating (that doesn't mean huge gaps, BTW). You want to make sure that the receiver doesn't rock fore-and-aft in the stock (imagine a teeter-totter) - if it does, it's not setting in the stock correctly - and once the receiver bolts are tightened the receiver will be put under stress which will affect accuracy. If you plan on "bedding" the rifle (which is a good idea) then you can be a little more relaxed about how you take off material when fitting the action to the stock since the bedding compound will fill gaps and give you a perfect fit.
The steps for completing the inletting are:
2) Remove the barreled action and take a bit of material off in the contact area using your weapon of choice - a file, dremel, or chisel will all work.
3) Repeat steps 1 and 2 until the barreled action sets in the stock solidly without rocking.
So, why would you want to replace the trigger? Most military rifles come with very "heavy" triggers - they have a lot of "creep" (distance to pull before the trigger releases) and heavy pull-weights. In a combat situation where adrenaline is running high, this is desirable as it makes firing the weapon into a deliberate action. For target shooting and hunting, however, a heavy trigger can be a detriment because it is nearly impossible to pull a heavy trigger without altering the alignment of the rifle - which again degrades accuracy. There are a couple of obvious solutions to this: 1) perform a "trigger job" on the stock trigger, or, 2) replace the trigger assembly with an adjustable aftermarket trigger.
There is a lot of good information out there on how to do trigger-jobs on military rifles, and while feel and pull-weight can be improved substantially (and it's the less expensive route), you will have a very hard time matching the performance of an aftermarket trigger assembly. Additionally (and more importantly) you can end up with a trigger that is dangerous if you don't know what you're doing (too light, prone to not being fully blocked by the safety, set off by releasing the safety, set off by bumping the rifle, etc) - so - you'll have to weigh the cost/risk/benefits. You could have a gunsmith perform the trigger job for you - but for the same money, you'd be well on your way to an aftermarket trigger. I have a decent amount of experience with trigger-jobs and while I've definitely been able to make improvements on stock triggers, I've yet to match the feel/performance of an aftermarket trigger. For me, an aftermarket trigger is a bargain - especially when I consider the "cost" of my time (I know, I know - "Why would I start considering that now?" lol).
Aftermarket triggers can vary quite a bit in price/performance as well - ranging from a very reasonable $40 to an extravagant $250+. The Bold trigger I chose for the Mauser cost a measly $38 and that's with a side safety ($33 without it), and the Timney trigger for the Mosin cost $88. Both are very nice adjustable-weight triggers and dramatically improve the feel and function of these rifles.
Step 4: Adding a Scope Rail
Unless you are one of the few blessed with "Eagle Eyes" you'll probably want to add some form of optic to your rifle. While there are a lot of different options in how this is achieved - including rails that clamp to barrels, rails that require drilling and tapping a receiver, rails that mount to existing sight bases, etc - I went with rails that require drilling and tapping the receiver because this tends to be lighter, stiffer, and less complex.
The rail I chose for the Mauser was the all-steel "Yugo 48" made by Ken Farrell. It's a very well-made rail that fit on the receiver of my Yugo 24/47 perfectly. Cost was average for a steel rail : ~$120. (NOTE: Ken Farrell no longer lists this rail on his site - but since it's a CNC part, I would imagine that he could make one upon request)
The rail I installed on the Mosin Nagant was from Rock Solid Industries. It's an aluminum rail that mounts at three points - and does live up to it's name. It's a very solid mount. Pricing is similar to the Ken Farrell mount at ~$110.
While mounting the rail isn't an uber-precise step (slight misalignment can be absorbed when sighing in your scope) - you still want it to be as precise as you're capable of. If you tend to be a bit ham-fisted, again, it might be worth paying someone who has the equipment. Your call.
Step 5: Making a New Bolt Handle
A lot of WWII rifles were fitted with relatively short bolt handles that jutted straight out of the rifle at the 3-o-clock position. While this was great for operating a bolt with bulky gloves and was useful when whacking open a sticky bolt with a hunk of wood, this configuration makes using a scope almost impossible since the scope interferes with the opening of the bolt. If your rifle has a straight bolt handle, you'll probably have to replace or modify it if you want to use a scope in the traditional location (as opposed to a "scout" scope out front). Since bending the existing one requires a LOT of heat and that the bolt body be well-supported when bending the bolt handle over (i.e. you really need a jig to do it), I opted to cut the stock one off and make my own bolt handle. I used a grade 8 bolt for the Mauser's new handle, but. the Mosin - being more akin to farm implement than fine watch - got a nail.... yes, a nail... one of those big honkin' timber framing nails provided a perfect piece of relatively hard stock. It seemed quite fitting - being Rrrrruuussian! - and has worked perfectly.
Step 6: Bedding the Rifle
"Bedding a Rifle" is the process of using a semi-liquid filler material that cures into a very hard final product to create a custom fit "cradle" for a particular receiver in a particular stock. The resulting near-perfect fit creates a very stable mechanical link between the receiver and the stock - and this stability in turn enhances accuracy. There are probably half a dozen or more materials that people use as "bedding compounds" - everything from adhesives like JB Weld and Devcon to more specifically engineered materials like Acraglas and Steel-Bed. My personal choice is Brownells Steel Bed. Steel Bed is very tough when cured and even more importantly it's working consistency is more like peanut butter than than honey-like, and therefore a bit easier to control. It does have the downside of more readily creating voids, but the ease-of-use makes that trade-off acceptable to me. As far as "release agents" - again - there are a lot of choices. Johnsons Paste Wax is a common one, but I used SynAir Synlube 1000 Release Agent which I use when molding urethane (so, I had it lying around) - and it worked flawlessly.
"Pillar-Bedding" is the process of installing metal "pillars" to precisely control the spacial relationship between the receiver and the "bottom metal" which consists of the trigger guard and magazine. This is especially important in wooden stocks where excess torque on the receiver screws, or, expansion/contraction from moisture, can compress the wood and distort the receiver .... and as we know by now, distorting the receiver can hurt accuracy. Pre-made pillars can be purchased from a number of vendors or custom made. I made the pillars for the Mauser out of aluminum and purchased the pillars for the Mosin Nagant from RockSolid Industries.
There are a lot of tricks and techniques to perform both kinds of bedding - and a lot of opinions to go along with those tricks and techniques. I won't go into those discussions but simply say that I chose to pillar-bed and liquid-bed both of my sporterized projects - both for the experience and the enhanced accuracy. The first time you do a liquid bedding job, it seems pretty scary - but again, if you take your time and prepare, it's not nearly as bad as it looks. It would be worth it to wander on over to YouTube and look up "bedding a rifle" - and watch a few videos - it will help you get an idea of methods you like and ones you want to avoid.
Step 7: Fitting the Trench Magazine
I'm including this step simply because you never know when you're going to have to get creative to make things work ;) In this particular instance, I wanted to add a trench magazine to the Mauser - but - most trench mags are designed for the longer receivers of the K98 Mauser and it's variants, and not the "short receiver" of the Yugo M48 or 24/47. The difference between them isn't huge - less than 1/8" - but it's enough that the parts for one don't fit on the other. To get the trench mag to fit, I had to come up with a different way of hooking the front of the magazine to the bottom metal while not compromising the function or alignment of the original floor-plate - i.e. I wanted to be able to switch out the floor-plate for the magazine as easily as removing the floor-plate (which requires just a button-push).
What I ended up doing was cutting the "hook" off of the front of the magazine, drilling a hole and brazing in a piece of drill rod. Then, I fabricated a catch block out of a scrap of shaft-key material. This was all done with files and a bench grinder - nothing fancy. Once I had drilled the hole in the catch block, I progressively sanded it down until the top of the magazine was held flush to the bottom metal with the block in place - then silver-soldered the catch block onto the bottom metal. Once Parkerized, It could *almost* pass for original ;)
Step 8: FInish the Stock
Again, there are a lot of ways to finish a stock - your choice. Paint, Tung Oil, Boiled Linseed Oil, Urethane, etc. After final sanding the entire stock, I applied a catalyzed urethane clear finish ..... mostly because I had some on hand. The product I used is formulated for industrial flooring, so, it's pretty tough. The disadvantage to a finish like this is that in the event of it getting damaged, repairs are a significant PITA. If you have the patience and time, Boiled Linseed Oil is a great choice.
Speaking of finishing, I was lucky enough to have access to a Parkerizing tank - so I used it to put a finish on these rifles. If, however, I did not have that access, I would have painted both rifles with a finish like Duracoat. I've used other finishes (paints), but nothing I've seen thus far compares to the durability and ease of application of Duracoat.
Step 9: Final Thoughts and Pics
As I mentioned in the intro, I think I enjoy the process as much as the final product. Both of these rifles went from fairly punishing to very enjoyable to shoot. In stock form, the Mosin Nagant was *really* unpleasant to shoot after about 10 rounds - but I've put over 200 rounds through it in one sitting in it's sporterized form and hardly noticed. Same goes for the Mauser (muzzle brakes help dramatically with recoil). Accuracy from both these rifles is *very* impressive with handloads (sub-MOA) - and much better than original with military surplus ammunition. This may not be the project for everyone, but if you like to give new life to old things and put a few gear-snobs to shame at the range, well, this might be something you'd enjoy :)